// <img id="pengfan" />

// 1.类型断言 as
const el = document.getElementById("why") as HTMLImageElement;
el.src = "url地址";

// 2.另外案例：Person 是Student的父类
class Person {}

class Student extends Person {
  studying() {}
}

function sayHello(p: Person) {
  (p as Student).studying();
}

const stu = new Student();
sayHello(stu);

// 3.了解： as any/unknow
const message = "Hello World";
const num: number = message as unknown as number;

export {};
